Dental fillings have been commonly used for centuries to fill cavities in teeth. Traditionally, amalgam fillings were commonly used as dental fillings for decades. Amalgam fillings include two or more metals of which one is mercury usually in the range of 40-50 percent. While these fillings have been in common use for over 150 years, there are a number of concerns with the use of mercury. Mercury, while generally considered safe for use in dental amalgams, does raise safety concerns both in use and in disposal later. Also, amalgam fillings permanently weaken the brittle crystalline structure of the tooth as the void left by cavity preparation is a permanent removal of integral material strength for the tooth, wherein the amalgam filling does not replace the void with a structurally integral element as the amalgam does not bond with the tooth as it must be retained with features to hold it in the tooth, further amalgam tends to discolor over time as well as being undesirably noticeable or visible, being typically bright silver in color that is in stark contrast to the near white tooth enamel color.
Composite fillings have become more popular replacing amalgam fillings as being much more structurally sound when disposed within the prepared cavity of the tooth, as the composite bonds as against the prepared cavity surfaces, thus helping to restore the structural integrity of the tooth that is lost to the prepared cavity to nearly that of a non cavity tooth. Composite fillings are typically a mixture of acrylic resins and glass-like powders. These fillings can be self hardening, that can require the mixing of substances-increasing the chances for undesirable air pocket porosity in the filling mixture, thus the use of a composite that doesn't require mixing is preferred, however, requiring to be cured with the use of ultraviolet light rays.
Composite fillings can be matched closely with the color of existing teeth, thus desirably rendering them practically invisible in relation to the tooth they are disposed in; further composite fillings are relatively durable and moderate in price. However, negatives are that the placement of the composite fillings into the cavities of the tooth can be difficult in order to eliminate any air pocket porosity or other voids where bacteria might be able to grow, or causing increased tooth hot and cold sensitivity, and further causing weakness in the combined tooth/composite structure.
Other types of tooth fillings include resin-reinforced glass ionomer fillings, porcelain fillings, ceramics, cast gold, and others. These fillings have a variety of problems associated with them and typically are not as commonly used as composites which are becoming the de-facto preferred standard tooth filling.
The process of filling a cavity with a composite filling requires initial preparation of the cavity by removing any decay, then cleaning and completely drying the cavity. Then thin layers of the composite filler material, being approximately one millimeter in thickness, are applied repeatedly with photo curing of each layer prior to the application of the next layer. Once the cavity has been filled with the layers of composite filling polymer, the final layer is shaped to the desired result in substantially conforming to the tooth outer surface, any excess composite material is trimmed and the final result is polished to achieve a smooth transition from the composite filling surface to the native tooth enamel surface.
The layers of composite polymer are each hardened within the prepared tooth cavity through photo-polymerization via the application of external energy, i.e. typically in the form of light. This process entails the use of a focused beam of light, usually ultraviolet or visible light. Typically, an ultraviolet light beam is focused on the applied layer of composite polymer which activates the resin causing the layer to harden. The composite polymer will shrink some during the photo-polymerization process, being typically about 2-6% which is undesirable in increasing the risk of air pocket porosity in the composite and weakened bonding as between the composite and the prepared tooth cavity. Since voids in the cavity can lead to bacteria growth, or causing increased tooth hot and cold sensitivity, and further causing weakness in the combined tooth/composite structure, thus it is critical to eliminate any such voids.
This results in the need for multiple thin layers of the composite polymer. Also, the polymer must be manipulated into the prepared cavity which is typically difficult to reach and relatively small in volume to ensure that no voids are created in the filling, all of which requires about 50% more time usually in completing the tooth filling with composites as compared to the prior art amalgam fillings that typically require less time to complete the tooth filling. Skilled dentists can ensure that the composite polymer material is properly applied by the feel of the dental tools in applying and manipulating the polymer material in the cavity as well as by visual inspection of the site.
The composite filling material curing light optimally should be positioned as close as possible to the composite material for maximum effectiveness, being a difficult task as the composite material is usually in a hard to reach location. Further, most conventional dental tools are formed from stainless steel or plastic materials and these materials reflect or otherwise interfere with the ultraviolet or visible light rays used to cure the composite filling material that not only causes inappropriate curing, but can also create damage to surrounding tissue in the mouth. Thus, conventional dental tools are typically not able to be used during the actual photo-curing process, resulting in the conventional dental tool and the curing light having to be used independently of one another, resulting in composite forming and curing having to be done as two separate operations, wherein if the dental tool could simultaneously form the composite to the prepared cavity while curing the chance of voids in the composite would be reduced along with less time being required via performing the two operations of forming and curing at the same time.
Another problem that often occurs with the conventional dental tool stainless steel and plastic materials is the adhesion of composite fill material to those materials while trying to form the composite filling material into layers within the prepared cavity. This creates additional problems in attempting to compact and shape the fill material not only during the curing process but even before the cure process. The adhesion of the composite fill material to the tool causes ripping of the material from the cavity and the creation of voids in the fill, often resulting in a greater chance of undesirable air pocket porosity and added time to complete the composite filling of the tooth. Furthermore, an added wetting agent is used to reduce the composite from tending to stick to the dental tool, however, this being undesirable due to the wetting agent interfering with the desired dry prepared cavity for composite bonding and again the added time to deal with the wetting agent as being an added step in the composite tooth filling process.
In the prior art in U.S. Pat. No. 4,666,405 to Ericson disclosed is a method and apparatus for polymerizing light-hardening dental fillings of class II type material, wherein a light transmitting frustroconical tip is screwed or pressed onto a fiber optic hand piece. Wherein the frustroconical tip in Ericson pushes the dental filling down into the dental filling as against a matrix band, see FIG. 3, and as the frustroconical tip is formed from an inverted cone shape with the narrow tip facing downward, the tip can be more easily removed from the dental filling and the matrix band. Again referring to FIG. 3 in Ericson, in can be seen that only downward pressure can be applied from the hand piece toward the tip, wherein Ericson does not teach forceful omnidirectional manipulation of the dental filling with the tip, as Ericson only teaches a single downward force movement of the tip into the dental filling.
Continuing in the prior art in U.S. Pat. No. 6,940,659 to McLean et al., disclosed is a cone shaped lens having increased forward light intensity and associated kits, wherein the lens forms a protective cover for the dental light curing device, with the primary goal of the lens is to minimize refraction of the light to help the light to have a higher intensity to cure the light curable dental filling. The McLean lens is of necessity thin in its cross sectional wall to aid in minimizing the light refraction and has a snap fit to the light device as shown in FIG. 3, further due to the broad or shallow cone shape, McLean does not come into contact with the dental filling composite material, as FIG. 4 shows the lens is at best only proximate to the dental filling composite material and also due to the thin wall thickness of the lens and broad based cone configuration, the lens is not taught to forceably manipulate the dental filling composite or even come into contact with it.
Further, in the prior art in United States patent application publication number 2008/0014546 to Sundstrom et al., disclosed is a tool for making a dental filing using a light transmitting tip configuration similar to McLean et al., wherein the tip is flexible having a loose fit over a light guide, see FIGS. 3, 10a, and 10b, thus allowing the easy changing of different tips on the light guide. Thus also as in McLean et al., in referring to FIG. 1 of Sundstrom et al., only downward force can be applied to the dental filling as against a matrix band due to the loose fit of the tool to the light guide and the flexible nature of the tool would teach against the forceable omnidirectional manipulation the dental filling via the tool.